The Tiger in the Bushes

by Joe Harvey - May 2000

I received a real mauling the other day down by the Veitch Creek on our property in Sooke where the cougars have been seen roaming. It was a surprise attack. I thought that I had taken all the necessary precautions but I was severely damaged. As a result I lay awake much of the night wondering whether I should go to Emergency. But let me go back to the beginning of the story.

My ‘gardening’ consists of finding plants which fit in seasonally (bulbs) or are vigorous enough to compete with the native vegetation with minimal help from me. I get them established by peripheral trimming of the adjacent plants and/or a squirt of Roundup. My favourites are then the ones which after that require no further help.

I have a sand and gravel lot, so drought resistance is important (and why my Rhododendrons are so poor). But alongside the creek where there is a little more moisture in summer, Inula species and Euphorbia griffithii cv ‘Fireglow’ have done particularly well.

Planted about five years ago the Euphorbia is aggressive, forming clumps 140 cm high by 200 cm wide. It has rhizomes but spreads only slowly pushing aside the weeds as it does so. This is my kind of plant!

In previous years the deer have chomped on my Euphorbias fairly constantly despite the poisonous latex in their stems. Deer are stomach fermenters so the bacteria in their rumen detoxify most poisons. However, in 1999, they had left the euphorbs alone.

During July I had been keeping an eye on the ripening fruit on the old Euphorb flower heads. There had been a good crop so I had been waiting for them to ripen to collect seeds for the Hardy Plant Group list.

On my daily walks I had been feeling the fruit to see whether they showed any sign of falling but they remained hard and firmly attached. During my stroll on 19 July I noticed that many of the fruit had suddenly disappeared. Something eating them? I was suspicious. Then I realised why the fruit were vanishing. These are exploding fruit and the hot day had caused them to scatter their seeds. I was then in a rush to collect the remaining seeds before they also vanished. So at 7:00 pm I took an empty 4 litre ice cream pail and secateurs down to the creek and proceeded to cut off the seed heads.

As you probably know, Euphorbias bleed latex when cut and the fleshy stems of E. griffithii are particularly prolific bleeders. The secateur blades were soon running with the white sap and there was plenty on my hands.

Returning to the house I was careful to thoroughly wash my hands since the latex is toxic. However, it had dried and was hard to remove, forming a tough skin of rubber on some fingers so I had to rub most of it off.

Pleased to get a good crop of seeds I eventually retired to bed to read the paper. Feeling sleepy I rubbed my eyes. The left one was sore so I rubbed it again. There was a burning sensation and it started to weep copiously. Realising what happened I leaped out of bed and scrubbed my hands really well this time. In a few minutes my eye had turned red and tears were streaming down my face.

What to do? Sleep was impossible with the burning pain. I had some antihistamine for allergies so I took a strong dose of it and after a few hours fell into a fitful sleep. By morning the eye had stopped watering but was still red.

So what happened? As a botanist with a fair amount of biochemistry under the belt I knew instantly what had happened. A trace of the sap had got into my eye. The eye, especially the conjunctiva, is particularly sensitive to irritants.

When I lived in Halifax I was on the Poison Control list of volunteer emergency plant identifiers and was aware that Euphorbs contain toxins. That was why I had taken care initially to wash my hands. It wasn’t a surgical scrub-up but it was more thorough than usual.

What had taken me by surprise was the quantity of sap required to produce such a reaction. With presumably only traces left on my hands, the quantity transferred to the eye must have been only a small fraction of this, the size of a speck of dust. This is what surprised me.

Many members of the Euphorbia Family are toxic. Seeds of the castor oil plant contain what has been characterised as the most toxic substance known so far. I presume that the substance in E. griffithii is identical or belongs to the same group of substances. Different species of related plants produce a host of variants of a basic molecular skeleton. I am also reminded that every Christmas questions arise as to the safety of those decorative poinsettas – E. pulcherrima.

Around the Caribbean another genus in the family, manchineel – Hippomane mancinella, is a heat and salt tolerant shrub or small tree common behind sandy shorelines. People sleeping under it or sheltering from the rain can be blinded by water dripping off the leaves. There is a real possibility of permanent eye damage, the scarring being severe.

Skin irritants of course occur in many other plant families. Poison ivy I have met personally. Then when I was in college some of my fellow students came across a stand of the giant hogweed, Heracleum mantegazzianum. They cut sections of the soft, fleshy stems and used them as tubes to blow through. A day or so later they developed red sores around their mouths where the sap had contacted their skin. The effect was similar to that of poison ivy and persisted for several weeks.

Haracleum differs from poison ivy in that it is a phototoxin, that is you have to be exposed to the sun to produce the reaction. An identical or related substance is found in parsley and here in Victoria we have the world expert on parsley biochemistry in Oluna Ceska. She has isolated and determined the quite complex molecular structure of the substance responsible (and has a tee-shirt with the molecule figured on it). Don’t let this stop you chewing on the sprig of parsley on your plate; you have to eat a big bunch to get the effect and then sunbathe.

Another toxic plant is Daphne. The seeds are particularly dangerous but some years ago my mother-in-law who was an excellent flower arranger decided to use some Daphne mezereum twigs with their scarlet berries in an arrangement. Instead of cutting the twigs she broke them. Now daphne stems are particularly tough and she obviously drove some of the sap into her fingers because she came out with a poison ivy-like syndrome.

Is there a moral in this? I think there is. Plants, the symbol of beauty and innocence, have teeth. Take precautions, keep you fingers out of your eyes when handling certain toxic plants. The kitchen is a hazard zone: cutting up hot peppers with bare fingers can get you into trouble at any orifice; even your ear will burn. Peeling potatoes and rubbing an eye can get a trace of solanine into it and cause watering.

Why do plants synthesize such substances? Protection. They cannot run away from predators so they make poisonous substances to lessen grazing. Virtually all plants are noxious in one way or another. It is no use saying you are only going to grow harmless plants – there aren’t many and if this is all you grow you will be host to most of the slugs, rabbits and deer in the region. Being aware is the correct attitude, take precautions, know your plants. There is no need to descend into paranoia, plants are not out to get you, they just need a little respect.

Most people think of plants as harmless, friendly things. I write this to warn gardeners that plants have claws too. The tiger in the bushes is not so dangerous if you know it is there. In the end it wasn’t the local cougar that got me, it was a plant.

This article was originally written for the Hardy Plant Group, July 21, 1999 and is reprinted with permission.